DRI3000

It's easy. Create user "switcher", configure your DM to autologin it, and set its session to a shell script like this:

while true; do if zenity --info --text 'Switch Session'; then gdmflexiserver; fi; done

Just tested it with Ubuntu and LightDM.

> Before we can assess the usability of your solution I think you need at least a few hundred users.

How are you going to find them? Most people don't need it. Those few who really need it are skilled enough to write one-line-shell-script themselves. :)

> Also, constantly running a second X server on tty1 wastes memory.

Yeah, about 10-15 MB. If that's too much you can replace `zenity` with console `dialog` and run similar script instead of getty. Unlike Windows there're lots of options. :)